Buttons and LEDs

The four buttons and four LEDs on the nRF52840 DK are
connected to dedicated GPIOs on the nRF52840 chip.

Table 1. Button and LED connection

Part

GPIO

GPIO alternative

Solder bridge

Button 1

P0.11

P1.07

-

Button 2

P0.12

P1.08

-

Button 3

P0.24

-

Button 4

P0.25

-

LED 1

P0.13

SB5

LED 2

P0.14

SB6

LED 3

P0.15

SB7

LED 4

P0.16

SB8

If P0.13–P0.16 are needed elsewhere, the LEDs can be disconnected by
cutting the short on SB5–SB8, see figure Disconnecting the LEDs. Since P0.11 and
P0.12 are used as a part of the Trace functionality, Button 1 and Button 2 can be
moved to alternative GPIOs, see chapter Debug input and trace
for more information.

Figure 1. Disconnecting the LEDs

The buttons are active low, meaning that the input will be connected to ground when the button
is activated. The buttons have no external pull-up resistor, and therefore, to use the buttons,
the P0.11, P0.12, P0.24, P0.25 pins must be
configured as an input with an internal pull-up resistor.

The LEDs are active low, meaning that writing a logical zero ('0') to the output pin will
illuminate the LED.